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In their advertising, EML indicates that this tube (hard plate) is based on the RCA 45, without saying which one. It doesn't look like any RCA 45 I have seen. Does it really sound like one?
What's the big deal?
Observe, don't think
Follow Ups:
Bought my 45 set second hand with RCAs. Rolled in the EML 45s.
Look and sound is quite different.
FWiW, I later got a pair of the EML Globe 45s which to my ear sound even better than standard EML.
My current tubes are Raytheon's, but not the 4 pillar box plate. (Mine have a sort of 4-edged star-shaped top mica, not the squarish one). I will buy a pair of EMLs. I already have what seems to be a pretty good pair of AVVT 2A3s. I'll add the EML 45s. Now if I could just find a pair of 98-102dB speakers for less than $2K that you don't have to build yourself and go down to an honest 40-45hZ.
Observe, don't think
Edits: 06/05/12
...why not set up a small woodshop and make some speakers? Shirley you can find a way to get the panels cut (the noisy part) and then just do the glue-up and trimming.
I doubt Tage Frid would approve but all my work, except cutting and routing, is now done in the spare bedroom with just a Workmate and hand tools.
Go ahead and build those 4Pis.
Calling an illegal alien an 'undocumented immigrant' is like calling a
drug dealer an 'unlicensed pharmacist'
That looks like a pretty darn professional job to me. I spent most of my time in wood shop being punished by the teacher!
Observe, don't think
...I promised not to take Spanish 2!
Calling an illegal alien an 'undocumented immigrant' is like calling a
drug dealer an 'unlicensed pharmacist'
On their web page, EML says "They have 4 four original V-shaped filaments like found in vintage 45 tubes."
The nonlinearity due to uneven cathode-grid spacing is a real effect, as Dennis alludes to. However, you must consider two further things: 1) it's the active surface of the space-charge electron cloud, rather than the emitting surface per se, that is important, and 2) other sources of nonlinearity include the mechanical precision of the grid (EML says "Wolfram grids allow the most precise grid wire distance, because wolfram is an extreme hard metal. This ensures better grid precision, which gives uniformity and better linearity at the low end of the tube curves...").
I would add uniformity of grid-plate spacing on theoretical grounds, but as long as the geometry is either flat or cylindrical (as in most 45s, 2A3s, 300Bs, and 845s), I believe that parameter is more easily controlled. Where you see it crop up is when the plate is a box construction while the grid is oval and the cathode cylindrical - many small signal triodes are built this way.
As for the RCA reference, EML says only "This tube has fully original specifications of the American RCA Type." Those specs do not include distortion, basically just mu, gm, and rp. EML does provide plenty of evidence that their tube is extremely linear, which RCA never did as far as I know. For what it's worth, the WE 300B original published curves are also extremely linear.
Incidentally, when I say "linear" I really mean that the mu does not vary significantly with operating point. All tubes still follow the 3/2 power law imposed by the physics; constant mu is as close to linear as tubes can get.
Just for the sake of clarity, Wolfram is Tungsten. Tungsten's symbol is "W" after the original name: Wolfram.
Wolfram may sound more exotic and by mentioning in their blurb that it's extremely hard, they give the impression that they're using a different material than most other manufacturers, which is not the case. Tungsten filaments are also used in light bulbs - which require very precise manufacture:)
The standard material for oxide-coated vacuum tube filaments is nickel. Tungsten is used in light bulbs because it has a much higher melting point, but oxide-coated tube filaments operate at a low enough temperature for nickel. Tungsten, thoriated or not, is used in high-voltage tubes where oxide coatings are too fragile to withstand high-velocity bombardment from stray ions - at least, that's the way I understand it.
I don't know the details, but I gather that when recent high-end manufacturers went away from round wire to a more flat construction, there were some problems with breaking filaments. It would be educational if Jac or someone who knows the real history would post, but it may be that there are proprietary technologies involved - and the internet is NOT a good place to keep industrial secrets!
Hi Paul. I know you don't like to have multiple posts per topic but as an example, Shugang Psvane and Treasure series are using tungsten filaments as do most transmitting tubes like most 10's, 845 etc. I was only mentioning the material as a difference between marketing and innovation. Also, using the name "wolfram" is misleading by giving the impression that it's a special or unique material when it's tungsten with or without special additives.
Good point - I just assumed that Wolfram was the word used in Czech, as it is in most Germanic and Slavic languages. So I figured it was more a translation issue than a marketing one.
Wikipedia has a pretty interesting article on the element. Among pure elements, only carbon has a higher melting point.
Yes, the material is called Wolfram in Czech (and other languages).
That is why its chemical symbol is W. English calls it differently -
Tungsten. So AVVT and EML call it by its international name.
The reason to use Wolfram (Tungsten) in filaments is as mentioned:
the Tungsten filaments do not burn as easily as Nickel filaments.
In any case, EML is talking about using it for grids, not for filaments. All their tubes use oxide-coated filaments, as do any 45s. Tungsten for Grids is probably not all that rare, I'd speculate. Rare grids were the gold-plated ones used by Western Electric, and later by a few modern tube manufacturers. (reduces secondary emission from the grid)
-Ed
It's the best 45 ever built and it's NOT an RCA (thank God!).
The filaments in a NOS 45 are folded into a "W" or "M" shape. A lot of 2A3s were built this way also-- and 300Bs like the Western Electrics. Trying to get accurate music reproduction out of any of these is a joke.
They are euphonic on certain kinds of music, always have high distortion levels, and also trash certain other music! Definitely for Euphonists.
For the objective of us who also hear well, EML is part of your ticket to real sounding music.
Learn how to use these properly designed tubes and leave the misdesigned New Old Stock stuff where it belongs-- in Museums.
---Dennis---
...all my RCA engraved base Cunninghams and National Union UX-45s... or maybe it's more of a whizzing sound...
Calling an illegal alien an 'undocumented immigrant' is like calling a
drug dealer an 'unlicensed pharmacist'
You gotta sell 'em to buy some EMLs!RCA/Cunningham SINGLE PLATE 2A3 was built right. It had a completely vertical filament system that matched the shape of its plate and grid system.
It was the best tube we had until the AVVT Mesh Plate.... it was slightly better than the EIMAC 75TL industrial tube. The AVVT guys also made us a good 45 with a similar, musically linear filament system..
EML is the big dog today.
What did the RCA/Cunningham SINGLE PLATE 2A3 do? It sounded coherent-- something RCA's Biplates and slant-filament 45s could not do. Music straightened out and got some religion. (The EIMAC 75TL triode is also musically coherent).
The Bottom-End wasn't anything to write home about, but all the octaves were represented-- maybe not fully. Mids and highs were good. Midrange voices-- both male and female-- and piano was good.
At one time a pair of these fetched $1000-$1600.00-- if in good condition.
Today, we have them beaten with modern tubes. Are they still good? They are.
I didn't discuss these before because they're hard to find, and we now have better.
---Dennis---
Edits: 06/04/12
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